Automatic telephone system



Se t. 6 19 f p 27 w. T. POWELL v AUTOMATIC TELEPHONE SYSTEM OriginalFiled Nl.

INVENTOR www ft M Sept.' 6,1927.

, l w..T. POWELL AUToMATc TELEPHONE SYSTEM 2 Sheets-Sheet 2 Filed Nov.

INVENTOR www UTIYUOJ bm oOo melo 0 OO oo 000.00 o o o M patentedY Sept.6, 19,27.

unirse STA-TES PATENT CFFICE.

WINERED T. POWELL or ROCHESTER, NEW-YORK, AssIGNoR To YTHE STROMBERG-CARLSON, TELEPHONE YMANUFACTuRING COMPANY, OE RoCHEsTER, NEWYORK,

,n CORPORATION or REW YORK.

AUTOMATIC TELEPHONE SYSTEM...

Reled for abandoned application -Seria'l No. 516,926, filed November 22,1921. This application :filed` August 4, 1926. Serial No. 127,094.

This application is a retile for abandoned application, Serial No.516,926, filed `November 22, 1921.

This invention relates to telephone systems and more particularly totelephone systems employingjautomatic switches in com-A pletingtelephone connections.

In some installations of automatic systems a switch known the Keith typeof line switch is employed. This switch is described on pages 38 to 45inclusive and 55 to 57 inclusive ot` Automatic Telephony by Smith &Campbell, iirst edition. v type oi' switch is also well known in the artso that it is not ynecessary to describe it in letail; In such systemsemploying the Keith line switch it was'customary to providesuch a lineswitch for each subscribers line, and the purpose of the presentinvention is to provide circuits whereby one line switch with the'addition of several springs will serve to extend two subscribers linesto idle trunk circuits. in other words it is the purpose' otthisinvention to vprovide circuits whereby a non-numerical switch will servethe purpose of connecting two subscribers lines toidle trunks, saidnon-numerical switch being of that type in which' commonl operatingmeans operates va plurality ot line switches.

The drawings with Fig. 2 below Fig. 1 diagrammatically represent aportion of a telephone system incorporating the present invention. Theportion of thedrawing at the lett of the dotted line in Fig. 1represents the primary line switch which serves Vto connect the lines ofthe subscribers A and B to idle trunks, `while the master switchmechanism .of this primary line switch is shown at the lett of thedotted line in Fig. 2. The portion ot the drawings of Fig. 1 includedvbetween the vertical dotted lines represents two secondary lineswitches, one of which is 'referred to as the odd secondary line switch,and the other is referred to as the even secondary line switch, althoughit will be understoody that there is common operating mechanism. foroperating both of these secondary line switches. A portion of thiscommon voperating mechanism is dia- This grammatically represented atthe right of the dotted line in Fig. 2. It will be'understood thait thesecondary line switches seize trunks leading to numerical switches suchasv selectors and connectors depending upon the size of the system inwhich this invention is employed.

For purposes ofthis description it will first be assumed that the`primary and secondary master switches haveV pre-selected idle primaryand secondary trunks for use.

Under these conditions, when the calling subscriber at A removes hisreceiver from its switch hook. a circuit is closed for the'slowreleasing line relay 5 from grounded battery, through the lower windingof this re lay and contacts 6 and 7, over the upper side ot the callingline and through the substation circuits in series, over the lower sideof the calling line through contacts 8, 9 and 1() to ground. The linerelay 5 is thus caused to attract its armature and thereby close acircuit from ground through the socalledpull-down coil 11, whichOperates theY armature 12and this in turn causes the F plunger (notshown) to -force the sets of spring contacts 13, 14. 15, 16, 17 and` 1Sinto engagement. The calling line will, therefore, be extended throughcontacts 19 and winding of the slow releasing relay 2O Ot the oddsecondary line switch to grounded battery and through contacts 21 toground.v The relay is actuated in this .circuit and closes an operatingcircuit from ground through the pull-down coil 22 of the Odd secondaryline switch, conductor 23, armature andk back contact of locking magnet24 to grounded battery. lVhen coil 22 actuates its armature 25 it opensthe circuit of the slow releasing relay 2O and closes the contacts 26,

'27 and` 28 by the operation ot its plunger (not shown). As soon asrelay20 is operated it closes a holdingcircuit tor the primary lineswitch from ground, lowermost armature and front contact of relay 20,spring contacts 13, conductor 29, contacts 3Q and the so-called Vbridgecut-off relay of the line switch to grounded battery.

When contacts 26 and 27 have been Operated the calling line A isextended throughv hoth windings in series ol the relay Bil of the tiretnumerical switch to ground and grounded hattery respectively.

Y Relay7 lil when operated actuales the slow releasing relay whichplaces the holding ground on conductor B-l, thereby completingl theholding circuit through contacts il and coil 35 of the secondary lineswitch to `grounded battery. It will also he noted that the coil 31 otlthe primaryY line switch is now held operated in inultiple with theholding conductor 3l, so that the primarif and secondary line switcheswill he niain tained operated until the time oi" release. The relay 3Qcorresponds to line relay7 L. l.

in the circuitot Fig. 53 on page 5T in the mentioned Automatic.releplion r by filinith t Campbell. lt is not necessary to describe theoperation ot such a nunierieal switch hut it is sullicient to know thatwhen a trunl; leading to auch a selector or connectm: switch is seized,a relaiY such as actuales the slow releasing rela);Y 33 to coinplete aholding circuit 'lor the nonsninnerical .switches of the connection, andthat at the linie ot diriestahlishing' the connection, the relaydeenergif/.es and shortly afterwards the slow releasing relaydeenergizes to open the nientioned holding circuit, to permit therelease of the ope 'ated primary and secondary line switches. Thisell'ected hy the deenergi- Zation ol the holding coil 3l ot the priniaryline switch and the deenergization olf the holding coil l5 ot the oddsecondarivv line switch. llhen these holding coils` deenergireniechanis'in not shown hut well known in this art, reinoi'es theplungers troni the contact hunks permitting the contacts such as lll,ll, l5, 16, 1T, i8, and to separate.

In the tirst part of this description, it was assunied that the masterswitches auch as those disclosed in Fig. il had alrcadi`- preselected anidle trunl circuitl lor use. The operation oi these master switches hywhich they select idle trunks will non* loe described. lllhen contacts1.3 the primaryV line switch were closed by the operation ot the plungerol this switch and when relayY 2O ol the seized secondary selector isoperatedi grouinl potential is applied to conductor lo indieating thatthis trunlt circuit is engaged. Art this tiine a circuit is closed overcondito tor itl through the contacts and wiper 5T ot the in. Sferswitch`r lelt hand winding olf start relaiv 3S to grounded battery.TWith relay Sti operated an actuatingI circuit is closed :tor thelockingniagnet lli), extending :troni grounded battery, winding ol thismagnet, 'front contact and armature olV relay 38, right hand winding otthe siipervisory relay lll to ground. Locking' 1nag net 239 attracts itsarmatures and thereliy perniits the spring (not shownll to advance theplunger operating arin and with it the Learner-io plunged: ol idle lineswitches of this n'roup (notsliown) to the next trunk circuit. ln theevent that one or hoth ot the next; pair ot trunk circuits is engaged,the test con-` tacts -ell and `l-:fl will he characterized hy thepresence ot ground potential 'so that start relai' 3S and consequentlythe loci; magnet will he still ope 'ated and the spring will ad- 1rancethe plunger operating arin into position helorc the next pair olf trunkcircuits.

lltl the leitet Fig. there will he seen two inetd-ated projectionsdesignated lil' and l5. rl'hese projections are actuated by the plungeer operating arni and are to positioned that when this arin has beeninored to its last position under the control ol? the mentioned spring,projection ll will close contacts liti whereupon the trip magnet eli'will he operaied in a circuit, traceable :troni grounded hattery windingot this` magnet5 contacts 4G, trout contact and arlnaturc of relayriltl. low resistance winding ofthe supervisory7 rela)v l0 to ground.rlhe trip magnet lil will attract its armature Ll-El which will "ne held.in this position by latch eti). This will close an operating' circuittor the solenoid flil which then actuales the plunger ope1.'ating arinto more it into its farthest position in the other direction at whichtime the pro jccion lo will cause latch all) to release the armaturefl-S. Freni this it will he seen that the solenoid actuates the plungeroperating arni in one direction and also places the spring under tensionwhich tende` to more the plunger arm in the opposite direction. .lhelanip {it} is an alarin signal which indientes to the attendant: thatsonic portion of the line-switch equiinnent ,has tailed to op erateproperly.

ln the event that it the suhscrilier at ll instead ol the suliscril'ierat il tl at initiate@ a callr the line rela)r 5 will he energized in acircuit including,l the upper winding ol the line rela;Y whereupon theprimary line switch will he operated in the inanner al ready dcsscrihodto close its contact springs 13 to 1S inclusive. lllhen this taltezsplace the relai7 (it) ot the eren iieiiondary line switch will heenergized over the two sides ot' the ailing line in series and willell'ect the o] ieration olf the even secondary line switch to seine atrunk circuit leading to a selector or connector depending upon the s)teni in which it .in used. It will he understood that the rela)r il() ofthe odd secondary line switch will not he operated at thinv tinie sinceits operating circuit will lie oi `en due to the fact that' the receiverat the substation A is on its switch lroolt.

het it he supposed that the suhscriher at, B initialen a call while thesililiiscriher al: A is calling. the primar);` line switch will,therefore. he already actunted in the manner already desclrihed. so thatcontact springs ll' and lS will he closed to complete a circuit;

- tion B to an idle secondary trunk leadingv for the slow releasingrelayVGO ottheeven,

secondary line switch which will then function to extend the callingline'fromsubstato a selector or connector switch.

It will be seen that the primary line switch of Fig. 1'will be heldoperated whilev a connection -is maintained from either of thesubstations A or Bl It' it is Lthe calling substation A that isVmaintaining the connection the primary line switch will beheldoperated4 over conductor 3,6, land if it is substation B that ismaintaining the connection, theV primary line switch will be heldYopera-ted lover conductor 62. p

yIn case the line terminating at substation A is seized as a called lineas soon as the con- Y nector switch (not shown) is stopped with itsbrushes in engagement with the terminals of this line and after` thetest thereof, then ground potentialis applied at this connector switchand is extended to conductory 29, thereby forming a circuit including`theupper winding of line relay 5A to groundedbattery. The line relay isenergized in this circuit and the primary lin-e switch operates in Vthemanner already described to close con-- tact springs 13 to 18 inclusive,whereupon y the circuit extending from ground at the connector switchwill be completed through the contact 13 and the winding of the cut-offcoil ot the odd secondary line switch. This coil 35 is effective to openthesprings 19 and 21 to prevent the operation of the relay 20 but itdoes not operate the plunger to extend the primary trunk to a selectoror connector switch. In the'event that substa-y tion Bv had been called,the, primary line switch would be operatedin asimilarl manner'but inthis instance the cut-off coil of the geven secondary line switch woulddisable its relay GO to prevent the Vprimary trunk from being extendedto a selector or connector switch. i ,Y

It will thus be'l seeny that circuit arrange# ments have been providedwhereby one nonnumerical switch of the plunger type is made individualto two subscribers lines. It will be understood, of course, that theremay be variations in the circuit arrangements described by the appendedclaims without de# parting from the spirit of the present invention. f

IVhat is claimed is y 1. In a telephone system, a plurality of telephonelines, a plurality of trunks, a plu rality of non-numerical switches,and motor mechanism common to said switches, each switch beingindividual to a group of several lines and operating on the initiationof a call over one of said lines to extend the linesot said group toidle trunks.

2. In a telephone system, a plurality ot'progressively movablenon-numerical switches, operating means common to said switches,

a pair of telephone lines terminating in each switch, a plurality oftrunk circuits each terminating in each of said switches, and meansoperated by the initiation ot a call on one of the telephone lines ot apair tor extending said lastlmentioned telephone line toa trunkcircuit.` y l k3.*In. a telephone system, a plurality of non-numericalswitches having spring contacts and actuating means for forcing saidspring contacts into engagement, operating mechanism common to theactuating means ot' said switches, two telephone lines and a pluralityof trunk circuits terminating in the, spring contacts of each s witch,and means responsiveto the initiation of a call on one of said telephonelines for causing the actuating means 0i its non-numerical switch toextend said calling line jto a trunk circuit.

et. In a telephone system, a plurality of progressively movablenon-numerical switches, contact springs and a contact spring-closingmember tor each non-numerical switch, operating mechanism common` tosaid mem# bers, a pair of telephone lines and pairs of trunk circuitsterminating in the spring con* tacts of each of said switches, and meansresponsive to the initiation of a call on one of said telephone linesfor actuating the related contact spring operating member to cause thecontact springs ot' the calling line and an idle trunk to be broughtinto engagement.

5. In a telephone system, a plurality of non-numerical switches, contactsprings and a contact-spring-closing member tor leach non-numericalswitch, operating mechanism common to said members, a pairof telephonelines and pairs otl trunk circuits terminating in the spring contactsotl each of said switches, and 'means responsive to the initiation-ot acall on .one of sai-d telephone lines for actuating the related contactspring opof the calling` line and an idle trunk to be brought intoengagement.

6. In a telephone system, a plurality of line switches, substantiallypassive contacts for each of said switches, two telephone lines and aplurality ot trunks terminating in each line switch, actuating mechanismfor the passive contacts of each line switch effect-ive on theinitiation of a call on either of its lines to connectsaid line to atrunk circuit, and operating means common to the actuating mechanisms ofsaid line switches.'

7. In a telephone system, a plurality of primary line switches, terminalcontacts and actuating means for the same in each switch, operatingmechanism common to the actuating means of said switches, a pair oftelev`phone lines extending to certain of the teriti ary trunksterniinating" in each of said set'- 'indary line switches, meanseffective on the niliation of a call on either ot the telephone linesoit :1 pair tor causingr the actuating means oiE the related line switchto seize a pair ot trunksleadinn" to idle `secondary line switches, andmeans tor automatically operating the secondary line switeh nowconnected to the calling line to extend said line to an idle secondarytrunk.

S. 1u a telephone system, a plurality of primary line switches, terminalcontacts and actuating' means iter the saine in eaeh switch, operatingmechanism eoinmon to the actuating means of said switches, a pair oftelephone lines extending to certain ot the terminal eontaets ot eaehswitch, trunk cir cuits arranged in pairs and multiply c011- nected toothers et said terminal contacts, a secondary line switch for each otsaid trunks, eoininon operating means for said secondary line switches,secondary trunks` terminating' in each `ot said secondary line switches,means effective on the initiation ot a call. on either oi the telephonelines ot a pair for causing the actuating means ot the related lineswitch to seize a pair ot trunks leadingr to idle secondary lineswitches, and inelans tor automatically operatingI the secondary lineswitch now connected to the Calling.;A line to extend said line to anidle secondary trunk.

9. In a telephone system, telephone lines, aJ plurality ot' trunks, aline switch individual to several ol? said lines tor exttaiding saidlines to separate idle trui'iks, means coninion to several line switchestor testing said trunks, and means to extend said selected trunks towanted telephone lines.

l0. In a telephone system; telephone lines, a plurality oit trunks, lineswitches individual to several 0i' said lines for extending said linesto separate selected trunks on the initiation ot' a eall, and means forselecting the trunks ahead of the calls.

11. In a telephone system, telephone lines,

Lettini-ie a` plurality ot primary trunlu-s, a. line switch individualto several oi said lines i'or extending said lines to separate idleprimary trunks, means for selecting primary trunks ahead ot the calls, asecondary line switch for each primary trunk, secondary trunksterminating in said secondary line switches ior extending calling linesand primary trunks on the initiation ot calls, and means i'or seleetingidle secondary trunks ahead ot the calls,

l2. In a telephone system, a plurality ot line switches oi the plungertype, two tele phone lines and a plurality oil trunks termi nating ineach line switch, and nie-ans responsive to the initiation oit a call onone ot said telephone lines tor causing the line switch ot said line toextend it to :in idle trunk.

13; In a telephone system, a plurality of. telephone lines, a pluralityot trunk eircuits, a line switeh individual to eaeh pair of telephonelines and having;l a plunger tor intercomieeting the calling; line and apre selected trunk, and a master switeh ior positioningl the plungers otidle line switches heitere idle trunks.

111-. In a telephone system, a plurality oli telephone lines, a purality oit priniary trunks, a line switch ot' the plunger type individual to each pair ot telephone lilies, a master switch eon'nnon tosaid line switches and operating to position the plungers olf idle lineswitches in a position to seize idle trunks when one of: their relatedtelephone lines initiates a call, secondary line switches ot the plungertype and master switch lnechanisni iter optnatini;` the plungers ol saidsecoiidary line switches, one ol said secondary line switches heiliglindividual to each primary trunk, and secoiidary trunk cir- Cults`terniinatiiigg,- in said secondary line switches.

In Witness whereof, .l hereunto subscribe my naine this 3rd day ofAugust, A. l). 1926.

VVINFRED T. POWELL.

Sil

